Process for the preparation of aminoanthraquinone sulphonic acids and new compounds obtainable thereby



Patented Nov. 1, 1 938 UNITED STATES PATENT OFFICE PROCESS FOR THEPREPARATION OF AMNOANTHRAQUINONE SULPHONIG ACIDS AND NEW COMPOUNDSOBTAm- ABLE THEREBY Henry R. Lee, South Milwaukee, and David X. Klein,Milwaukee, Wis., assignors to E. I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationFebruary 24, 1937,

Serial No. 127,566

6 Claims.

This invention relates to a new and improved process for the preparationof sulphonic acids of the 1-aminoanthraquinone compounds which carry nosubstituents in the beta-position ortho thereto. The invention relatesfurther to the prepartion of new and valuable substituted 1-aminoanthraquinone-2-sulphonic acids which are obtainable by thisprocess.

Several processes for preparing 1-amino-2- anthraquinone sulphonic acidare described in the prior art, some of which have been employed on acommercial scale more or less successfully. A rsum of these processes isto be found in U. S. Patent 1,871,466 of August 16, 1932, which isitself directed to an improved process for preperatures below 145 C. arenot recom d paring this particular compound. These procsince at thelower temperatures the time for esses, however, due to the strenuousconditions of effecting complete conversion is unnecessarily thereaction, are limited chiefly to the preparaprolonged. Since t ereaction takes Place tion of the unsubstituted 1-amino2-anthrareadily atthe lower temperatures, those above quinone sulphonic acid, for manysubstituents about 195-200 C. are not necess ywhich may be introducedinto the anthraquinone The following examples are give 10 more fullynucleus are either removed or altered by such illustrate our new andimproved sulphonation strenuous sulphonating conditions. Due to theprocess and the pre ofnew and valuable high temperatures heretoforeemployed, certain dyestuff intermediates. v

side reactions also take place with the result that theoretical yieldsor even approximate theoretical Exwmple 1 yields of the resultingalpha-aminoanthraquinone sulphonic acid cannot be obtained.

We have found that alpha-aminoanthraquinones can be readily sulphonatedin the adjacent beta-position by subjecting them to the action ofchlorosulphonic acid in an inert highboiling solvent such asortho-dichlorobenzene, tetrachloroethane, trichlorobenzene,nitrobenzene, etc., at temperatures of around 150 C., and that theproduct can be isolated in exceptionally high purity directly from thesolvent mass in yields substantially equal to theory. By this process weare able to prepare new anthraquinone derivatives from which new andvaluable dyestufis may subsequently be prepared. This new sulphonationprocedure makes possible the production of new 1-aminoanthraquin0ne-2-sulphonic acids which contain simple monovalent substituents and alsoheterocyclic substituted aminoanthraquinone sulphonic acids, such as,for example, 4-amino-N-methyl 1,9) anthrapyridone-3-sulphonic acid, andsimilarly con-.- stituted bodies.

0 In this process the first reaction of the chlorosulphonic acid andalpha-aminoanthraquinone apparently gives theanthraquinone-l-sulphaminic acid, which upon heating in the inertsolvent is rearranged to the I-amino-Z-anthraquinone sulphonic acid in amanner similar to 112' parts of l-aminoanthraquinone, finely powdered,aresuspended in 500 parts-of orthodichlorobenzene and 64 parts ofchlorosulphonic acid are slowly added thereto under agitation. Thetemperature rises to 50-60 Cpand an even gray color is taken on by themass. The mass is then heated to 150-155 C. and heldfor 4 hours. Thel-amino-2-anthraquinone sulphonic acid may be isolated by filtration, orthe entire mass may be steam distilled to free it from solvent and theaqueous solution used directly for subsequent operations or salted toisolate the alkali-metal salt. A yield of from 95 to 98% of theory offree acid is obtained.

Example 2 137.5 parts of 5-nitro-l-aminoanthraquinone,

finely powdered, are suspended in 500 parts orthodichlorobenzene. Whileagitating, 64 parts chlorosulphonic acid are slowly added and the massis heated to 170 C. for 8 hours, then cooled to room temperature. The1-amino-5-nitro-2-anthraquinone sulphonic acid may be isolated byfiltration, or the mass may be steam distilled to remove the solvent,with subsequent filtration and salting. Substantially theoretical yieldsare obtained. t

compounds being sulphonated, although tem-.

, obtained.

Erample 3 137. 5 parts of B-nitro-l-aminoanthraquinone,'

phonic acid are slowly added thereto under agitation. The temperature isslowly ralsed to 170 acidimay be prepared by the Same procedure C(andheld for 8 hours. By working up as in Example 2 an exceptionally, ,highyield of; ll-l amino-8 -nitro-2-anthraquinone/sulphonic acid is Example4 141 parts of 1-amin0 5 methoxyanthraduinone aresuspended in 700 partsof ortho-dichlorbent j 111500 partsof zene, and after agitating a shorttime to insure dispersion, 64 parts of chlorosulphonic acid are slowlyadded. The temperature israisedto'150- 155 C. and held for 4 hours. Itis then diluted withwater made slightly alkaline by the-addition 'oussolution of l-amino-5-methoxy52 anthraquinone sulphonic a'cid sodiumsalt thus obtained may be used directly, or may be salted to isolate thel-amino-5 methoxy-2 anthraquinone sulphonic acid in the form of itssodium salt.

-' a p 1 L r orthol-dichlorbenzene there are suspended 1 29 parts of1-amino-5-chloranthraf quinone, finelypowderedr 64*'parts of chloro- Vsulphonic, acid areslovvly added under agitation,

' the temperature'israised to l-l55'C and held for 8 "hours, ,The1-amino-5-ch1oro-2 anthra- .35

quinone sulphonic acid "may be isolated by the procedure v ;i ascribe(lj in the preceding examples.

"Ex ple l 159 parts "or 1:aminO-a nm umn Sill phonicfacidfare suspendedin' 500 parts of'ortho dichlorobenzene- 64- p'arts' of chldrosulphonicacid are :added "under" agitation and the mass is heated to 1150455cl-for lhourst The solvent is removed bysteam distillation." *The'volume is brought to 1500 parts'v'vith the addition of :wa-

ter, and parts of a 78% solution'of sulphuricl 'acid are added. Theunchanged l-aminoanthra-' quinonei-5-sulphonic'acidisfiltered o'fi; 'Thefiltrate' contains l'-arriino-'2,5'-disulphonic acid in good yield;whichmay be isolated by s altin'g. a Among the' new compounds which maybe pre pared by this process are the I-aminO-Z-anthrm,

quinone sulphonic "acids containing in" the oppof site-benzene ring 'ofthe anthra'quinone nucleus substituentsof the class consisting. ofnitro, chloro, methoxy, sulpho and c'arboxy groupsyas more particularlyillustrated by the above' ex amples. The 6-chloro-, 7-chl0roand8-chloromethoxy-substituted compounds, such as the 6-- rnethoxy- 1-amino- 2 -anthraquinone V sulphonic outlined in. Example l, using theG-methoxy-laminoanthraquinone as the starting material.

. The isomeric sulphonic acids, such as the lamino.-'2,6-'and"'2j8.-disulphonic acids may also be prepared by the. process moreparticularly described in Example 6.

In all of-the above'mentioned cases the sulpho! nation is effected atrelatively low temperatures fcompoun'ds are obtained. 1 7 I V 1 Weclaim: 1 r

1-amino -a nthraquinone in ,an' inert high-boiling and substantiallytheoretical yields of very pure 1. The process which comprisessuspending a I orgamesowem; reacting-t e" same therein with'chloros'ulphonic acid and raising the temperature of the mass'tocomplete the sulphonationI V 2.'The process'whichc'omprises suspending1a l-amino anthraquinone in an inert high-boiling organic solvent,reacting the sametherein with chlorosulphonic acid, and he atling ithe,massto' temperatures above 'C.--

3. In the "process for preparing I-amino Z- anthraquinone sulphonic acidthe steps which comprise heating al-aminoanthraquinone in an 1 inerthigh-boiling organic solvent'with chloro- 'sulph'onic'acid attemperatures above 145513.; 1 and filtering of: thel-amirlo-Z-anthraquirione sulphonic acmrrom the reaction mass; 4i As newcompounds, the l-amino-2-anthraquinonejsulphonic acids which carrya-monova lent substituent 'of the class consisting of ,NO2,

SOI-I*, and 001 1;; in the benzene ring of the 'anthraquinone nucleusopposite the one towhich; the aminoand sulphonic acid groups'are at 1 rtache'dQthe NO '2 group'when present beingin onef'of thepositions 5 and8, and which may be- 'p'eratures" of 145 C. and above.

preparedbyheating the corresponding substi itutedl-am'inoanthr'aquino'ne in an inert high; 3 boiling solvent withchlorosulpl onic acid at tem'f 5. As a' new 7 compound, 1-amino- 5-nit'ro1-2 anthraquinone sulphonic acid.

, hone'sulph'onic acids which carry in the benzene ring remote'from thatto which the amino and -6. As new compounds, I-amIn -Z -anthraiiui fsulphonicacid groups are attached a second s u1,-

phonie acid radical. I

' H R R- 7 DAVID KLEIN..

